Someone told me that the boat will actually go faster with a slightly rough surface below the waterline. Is this true?


yes, sorta, not really. first slightly rough is the difference between glossy and and 400/600 grit wet dry. the theory is if the water sheens on the (sanded) surface vs beads on the (glossy) surface. The sheened surface will have slightly less surface tension. the difference is extremly small. not really measurable.

IMHO not worth it. and the surface will be hard to keep clean.